Grinding machine



, Dec. 18, 1928.

P. CONRADSON GRINDING mclu'ma Filed Feb. 15, 19231 3' Sheets-Sheet l Dec. 1'8, 1928.

P. CONRADSON GRINDING MACHINE Filed Feb. 15, 1923 3 sheets sheet 2 Dec. 1a, 1928. V

P. CONRADSON I GRINDING mcnnm Filed Feb. 15, 1925 a Sheets-Sheet 3' Patented Dec. 18, 1928.

.UNITED STATES rnnn'rrcn connans on, or EVANSVILLE, Wisconsin, AssIeNoa, BY mn'snn .nssren- MENTS, r THE HEALD Macnmn COMPANY,

conro'na'rxon or mssacnusn'rrs.

0F WORCESTER, 'MASSACHUSETTS, A

GRINDING MACHINE.

Application filed February 15, 1923. Serial No. 619,124.

This invention relates to a grindingmachine of the type which is more fully disclosed in my copending application Serial No. 619,122 filed February 15, 1923 and the invention relates more particularly to improvements in the grinding spindle carriage driving ineans which eliminates-the difiiculp ties of this prior arrangement and greatly in-'- 0 creases the life of the belt; in which the weight of the carriage is balanced and dis? tributed in a way to minimize vibration; in

which all overhead driving belts are dispensed with; which provides a very compact 26 and unitary construction; and in which the driving motor and driving connections are enclosed within the machine so as to-be entirely out of the way.

I accomplish these objects by mounting the 30 driving motor on the underside of the carriage beneath the spindle of travel with the carriage, the motor and driving connections being enclosed by the machine base and the carriage housing.

duce an improved carriage which is of a very. simple and durable construction so that it vmay be-operated satisfactoriiy at high reciprocating speeds and embo ies no devices 40 which are apt to get out of order or'caus'e trouble in use, and. to this end the carriage is provided with improved meanswhich onerates hydraulically to reciprocate the carriage'. a Another object. is to produce a'carriage which combines the said driving means an reciprocating means in a unitary compact;

-- base and H extensions of the sides 15, each extension pro- I structure. 1 v I A further objecti's to provide improved 0 means for guarding or protecting the carriage ways against grit, water, or other foreign substances. 1 .In the acompanying drawings, Fig.1 is a view partially in eleyational and partially in Another objectof the invention is to pro of the carriage moving the grinding w longitudinal vertical section througha grinding machine embodying the feature of my inv vention. Fig. 2 is a transverse vertical section taken in the plane of line 2-2 of Fig. 1. Fig. 3 is a perspective view somewhat diagrammaticillustrating the means for guarding or protecting the supporting ways for the carriage.

Fig. 4 is an axial section through the grinding spindle and its bearings.

. Fig. 5 is a diagrammatlc view showing the carriage in sideelevation and the hydraulic means for operating the carriage.

Wlnle my invention is susceptible of varlous modifications I have shown in the drawings,- and will herein describe in detail,-the

derstood that I donot thereby intend to limit theinvention to the exact construction disclosed but. aim in the subjoined claims to cover all modifications and alternative con referred embodiment, but it should be unstructions falling within the scope of the in- .vention.

- The machine shown in my copending application above referred to,

adapted for internal grin-din and comprises a bed or base, a head stock aving a rotarylongitudinally of the bed toward and away from the head stock. The carriage has a spindle with a grinding wheel thereon to enter the bore in the work in said chuck-or fixture to grind said bore, the reciprocapliori ee lengthwise of the bore.

The base of the machine is herein represented-as comprising two side walls 10 and two end walls 11 and on the upper edges of the sidewalls are formed guide grooves or ways 12 to receive V.-shaped guides or ribs 13 on the opposite sides of the carriage body 14.

d I The sides 15 of the carriage body overhang I and of which the present carriage forms apart, is specially.

the upper edges of the sidewalls 10 of the r the guide ribs 13 are carriediupon and ways 12 and extend the full lengthof said 7 ways, each guard plate having its inner edge,

that is the edge next to the inside of the ma-' chine, suitably secured to the upper edge of one'of the base walls 10, the plate extending o utwardly abpve the ways 12 and ribs 13 and being curved/downwardly at its outer edge into the space provided by the peculiar shape of the side 15 ofthecarriage body before described. The outer lower edge of the guard plate is in a plane lower than the upper edge of the adjacent way 12. In grinding machines, it is customary to use water or other coolant which becomes mixed with abrasive and foreign substances and this liquid is very apt to be splashed upon the guides of sliding parts and would rapidly wear these parts due to the contained abrasive: The guard plates 16 eflectively protect the ways 12 without interfering with the movements of the carriage. A-Vertical plate 16 is fixed to and depends from the front end of the carriage to prevent.

coolant from being splashed upon the driving motor.

In the upper part of the carriage is mounted a rotary spindle 17- having a grinding wheel 18 on its free end, the spindle being mounted in and forming part of a demountable unit which is removable as a whole from thecarriage. This unit comprises a sleeve 19 having external conical surfaces 20 to fit into.

fixed a pulley 23. In the exemplary form shown in the drawings the external diameter of this pulley 23 is less than the internal di'-' ameter of nut. 21 so that when the nut is removed, the sleeve 19, spindle 17- and pulley 23 may be withdrawn asa whole from the carriage. If the pulley is of greater diameter than the interior of the nut the pulley will be removed before withdrawing the spindle.

-A belt'24 runs over the pulley 23 and'over pulley 25 on the armature shaft of a motor 26 which is bolted to the under side of the carriage and occupies the space between the sidewalls 10 of the machine base, the motor being positioned beneath the horizontal plane offthe'ways 12. By locating the motor in this manner many beneficial results accrue, among which are increased life of the driving belt by eliminating the travel of the belt along its driving drum as in prior machines; the dispo'sition'of the main weight of -the carriage.

eneath the ways 12 thereby reducing vibration; the compactness or saving 'of space which the arrangement affords; and the safety which results from the elimination of overhead or otherwise exposed belts.

A suitable belt tensioner for the belt 24 is provided comprising, in the present instance,

an arm 27 pivoted at 28 and carrying on its free end a pulley 29 which is pressed against contributes greatly to accuracy as well as inacetates the belt by means of a compression spring 30. The carriage is arranged to be reciprocated cates with the carriage. In the present instance, this cylinder is provided with integral flanges 31 which are bolted to depending portions of the carriage, the motor 26 being 1n turn bolted to the underside of said flanges.

31. A piston 32 in said cylinder is stationarily mounted in the end walls 11 of the machine base by means of hollow rods 33 projecting axially from the ends of the piston through the ends ofthe cylinder. Preferably the rods 33 and the piston 32 are turned from an integral piece of metal; Through these rods the actuating fluid (preferably oil) is introduced into the cylinder on opposite sidesof the piston head 32, the rods having transverse bores 34 adjacent to the piston head 32 through whichthe fluid passes from the rods into the cylinder and vice versa.

The cylinder and the rods are almost wholly enclosed by a stationary housing 35 that is suitably mounted on the machine base, the lower side of the housing being open to accommodate the .parts on the lower side of 131%6 carriage and permit reciprocation there- 0 The remote ends of the tubes 33 are connected by pipes 36 with a main control valve 37 which governs the admission of the actuating fluid to and its exhaust from pipes 36 and hence the cylinder 31. This control valve 37 is actuated by a lever 38 pivoted at 39 on the machine base, the lever having a projection which is arranged to be alternate-- ly engaged by dogs 40 fixed on the carriage to swing the lever,

This results in reversing the valve 37 and alternately admitting pressure fluid into one end or the other of the cylinder and exhaustmg it from the opposite end. The grinding wheel 18 is thus caused 'to reciprocate lengthwise in the bore of the piece of work A,-Fig. 5. The actuating fluid is delivered to the control valve through a pipe 11 from a pump or other suitable source 42 and the oil escapes from the valve into a receptacle, not shown, from which the pump draws the oil. Y

It will be noted that the cylinder 31 is also located beneath the horizontal plane of the ways 12 thereby increasing the proportion of the weight of the carriage which is located below said ways with the beneficial results already described.

By use of the hydraulic reciprocating .means herein disclosed, I am enabled to reci rocate the carriage at very .high speeds wlthout shock at the ends of the stroke and without lost.motion or uneven movements of travels back and forth in contact with'the work at a constant and even speed -which stant source of trouble.

ed on said base,

creased output. Furthermore, with this. eliminate reversing gearing or mechanism I clutches of all kinds which are usually employed in reciprocating mechanisms for this purpose and which have proven to be a con- I claim as my invention: f 1. A machine of the character descrlbed havmg, 1n combination, a base, a carriage mounted for reciprocation on said base, a

rotary spindle in said carriage, said carriage having a depending bracket extending into said base, a piston and cylinder unit having one element supported by said bracket and havingthe' other element stationarily mount: a motor mounted on the under side of said bracket below said piston and cylinder unit, and means for supplying fluid to said cylinder and exhausting it therefrom to efiect-reciprocation of the carria e. 2. A grinding machine having, in com ination, a base, a carriage mounted for reci rocation on said base, a rotary spindle in sa1d carriage, said carriage having a pair oft spaced depending brackets extending into said base, a piston and cylinder unit for driving said carriage brackets, means for supplying fluid to said cylinder and exhausting it therefrom, and a motor mounted on the underside of said carriage and bridgin said brackets.

mounted between said 3. A grinding madhine having, in combi nation, a base having closed side walls formed with a pairof parallel ways on their upper edges, a carriage mounted for recipro cation on said ways, a pair of spaced brackets depending from said carriage into opposite sides of said base, a piston and cylinder unit 'for driving said carriage, said unit extending between said brackets, one element of said unit being rigidly secured to said base and the other element of said unitbeing supported by said brackets, means for supplying and exhausting fluid to and from said unit, and a motorinounted on the underside of said carriage and bridging said brackets, said unit and said motor being located near the horizontal plane of said ways.

In testimony whereof, I have hereunto afiixd my signature. 4

PRENTIOE OONRADSON. 

